Method _calculatePadding

src/core/core.scale.js:689–737

(first, last, sin, cos)

  }

  _calculatePadding(first, last, sin, cos) {
    const {ticks: {align, padding}, position} = this.options;
    const isRotated = this.labelRotation !== 0;
    const labelsBelowTicks = position !== 'top' && this.axis === 'x';

    if (this.isHorizontal()) {
      const offsetLeft = this.getPixelForTick(0) - this.left;
      const offsetRight = this.right - this.getPixelForTick(this.ticks.length - 1);
      let paddingLeft = 0;
      let paddingRight = 0;

      // Ensure that our ticks are always inside the canvas. When rotated, ticks are right aligned
      // which means that the right padding is dominated by the font height
      if (isRotated) {
        if (labelsBelowTicks) {
          paddingLeft = cos * first.width;
          paddingRight = sin * last.height;
        } else {
          paddingLeft = sin * first.height;
          paddingRight = cos * last.width;
        }
      } else if (align === 'start') {
        paddingRight = last.width;
      } else if (align === 'end') {
        paddingLeft = first.width;
      } else if (align !== 'inner') {
        paddingLeft = first.width / 2;
        paddingRight = last.width / 2;
      }

      // Adjust padding taking into account changes in offsets
      this.paddingLeft = Math.max((paddingLeft - offsetLeft + padding) * this.width / (this.width - offsetLeft), 0);
      this.paddingRight = Math.max((paddingRight - offsetRight + padding) * this.width / (this.width - offsetRight), 0);
    } else {
      let paddingTop = last.height / 2;
      let paddingBottom = first.height / 2;

      if (align === 'start') {
        paddingTop = 0;
        paddingBottom = first.height;
      } else if (align === 'end') {
        paddingTop = last.height;
        paddingBottom = 0;
      }

      this.paddingTop = paddingTop + padding;
      this.paddingBottom = paddingBottom + padding;
    }
  }

  /**
	 * Handle margins and padding interactions